I kno someone already posted about this but the thread didnt seem very clear.

When my car is turned on initially the oil pressure gauge reads about 30 psi at idle and around 60 psi in gear. However, after the engine heats up the gauge will then read about 15 psi at idle and about 30 psi in gear.

It's ok for oil pressure to drop as the engine heats up, the oil becomes thinner as it warms up. The pressure is rpm based, reading higher as engine revs up. The weight of the oil (10W40, 10W30, 5W30, etc) is the deciding factor in how high the pressure is at both warm and cold. Your pressure sounds about typical for a lower weight oil.......

Not really sure what that could mean. The sending unit may have been partially blocked before and is now reading correctly. I'm not familiar with the Z32 oil pressure guages and sending units, maybe Spongerider can provide an answer here. I know with my Z31, the pressures were all over the place as yours are. With the weight of oil I was running, 15W40, I'd see pressures as high as 60 psi at idle when cold, dropping off to 15 psi at idle at full temperature. The unit never failed, so I imagine that's what it was supposed to be reading.

If your oil has been in the engine for a while and seen any extreme temperatures, maybe it's time for a change. Oil can sheer down to a lower weight after a while, you may be seeing the effects of this through the guage.